OpenLog is an open source data logger. Simple to use, simple to change. We wanted to create a serial logger that just worked. Power up this device and it will start logging any received serial data at 9600bps. Sending Ctrl+z three times will drop out of logging and in to command mode. ‘new’ will create a new file. ‘md’ makes a directory. ‘?’ brings up the list of commands. OpenLog doesn’t do a lot, but it does log serial streams extremely well. Example:

>new testfile.txt
>append testfile.txt
<(send large amounts of text followed by three ctrl+z characters)

That’s really it! OpenLog firmware is open source and is based on Bill Greiman’s sdfatlib. OpenLog currently supports FAT16 and FAT32 microSD cards (we’ve tested up to 64GB!).

All the design files (schematic, PCB layout, firmware) are open source released under the CC-SA v3 license and are available through GitHub.

Note: New firmware is available which allows the OpenLog to be used in Arduino 1.0 and also allows for higher baud rates. Check the links below for more information.

Features:

Log to low-cost microSD FAT16/32 cards up to 16GB

Simple command interface

Edit config.txt file from a computer to change baud rate and other system settings

Three modes:

NewLog creates a new log every power up and immediately starts logging

SeqLog appends a file called “SeqLog.txt” at every power up and immediately starts logging